The invention pertains to motor vehicle electric door locks.
An adjusting device for motor vehicle door locking systems is shown in U.S. Pat. No. 3,243,216. This adjustment device has the advantage that in the end positions the output element is completely decoupled from the drive motor, so that a smooth, manual adjustment is possible. Furthermore the relatively small amount of control apparatus for the drive motor is advantageous. The drive motor in this arrangement only rotates in one direction of rotation. However the arrangement of U.S. Pat. No. 3,243,216 does function reliably under certain conditions. If the operating voltage is high or low, it is possible for the crank to stop in a position away from its parking position in which it is not possible to adjust the slide. The slide is coupled with the push rod via an overload spring which permits the push rod to be changed over from one end position into the other end position even if the adjusting motion of the slide is blocked. However, a great amount of force is necessary to effect the changeover because the overload spring must be laid out in such a way that it can transmit the normally necessary adjusting force of the output element. However in most applications the push rod is operatively connected with the lock of the motor vehicle door and in practice the door lock can no longer be unlocked by means of the key.